1. Field of the Invention
The present invention relates to a method for manufacturing a semiconductor light emitting device having a structure obtained by forming an n-type semiconductor layered portion, a light emitting layer and a p-type semiconductor layered portion (each made of a group III nitride semiconductor, for example) on a group III nitride semiconductor substrate. Group III nitride semiconductors are group III-V semiconductors employing nitrogen as a group V element, and typical examples thereof include aluminum nitride (AlN), gallium nitride (GaN) and indium nitride (InN), which can be generally expressed as AlxInyGa1-x-yN (0≦x≦1, 0≦y≦1 and 0≦x+y≦1).
2. Description of Related Art
A semiconductor light emitting device having a structure obtained by growing a group III nitride semiconductor layer on a GaN substrate is known in general. Typical examples thereof include a blue light emitting diode and a blue semiconductor laser. In the case of the semiconductor laser, the group III nitride semiconductor layer has a multilayer structure obtained by successively stacking an n-type AlGaN cladding layer, an n-type GaN guide layer, an active layer (light emitting layer), a p-type GaN guide layer, a p-type GaN electron blocking layer, a p-type AlGaN cladding layer and a p-type GaN contact layer from the side of the GaN substrate, for example. The active layer has a multiple quantum well structure obtained by alternately repetitively stacking quantum well layers consisting of InGaN layers and barrier layers consisting of non-doped GaN layers, for example. According to this structure, electrons and positive holes are recombined in the active layer to emit light. The emission wavelength can be adjusted through the In composition in the quantum well layers.